The World at Risk

Invasive species are not only a problem in New York state—
they are a problem worldwide. As residents of New York state,
we contribute, accidentally or on purpose, to that problem.

Just as people have brought invaders here for centuries, people have moved plants and animals native to
New York state and North America across our country and around the globe. We are both the victims of, and the cause of, the spread of invasive species.

Barbara Tokarska-Guzik, Bugwood.org

Black Cherry

Prunus serotina

Black Cherry is native to the United States.
It was first brought to western Europe in the
early 1600s as an ornamental plant. Since
then, it has been planted widely in eastern
and western Europe as an ornamental and
as windbreaks in forest and open agricultural
areas. Local spread is from seeds dispersed by
fruit-eating birds and mammals.

Black Cherry can shade out the growth of native ground
vegetation and hinder regeneration of native
forest trees. The leaves it drops may be
allelopathic and can poison livestock.

Pinewood Nematode

Bursaphelenchus xylophilus

Pinewood Nematode is a microscopic roundworm native
to the United States. It was first detected in southern Japan
in 1905. It was probably introduced in a shipment of timber
or packaging material. It has since spread into Taiwan,
South and North Korea, and China.

It attacks the
vascular tissue of pines native to Asia, which can
result in pine wilt (a non-native disease) and the death
of infected trees within one year. In Japan, as many
as 20 percent of the trees in some forest stands have
been killed as a result of this introduced species.

The
Pinewood Nematode has a high reproductive rate and
can survive extreme conditions, such as drought, low
temperatures, and lack of food. In North America, most
native species of conifers are resistant to the wilt disease.

Ohio State University, Ohio Agricultural Research and Development Center

Whitney Cranshaw, Colorado State University, Bugwood.org

Grape Phylloxera

Daktulosphaira vitifoliae

Grape Phylloxera is an aphid native to
eastern North America. In the 1860s, it was
introduced in France, probably attached to
the root stock of imported American grape
vines. The native European grape vines were
very susceptible to the insect. By the end of
the 1870s, 60 to 90 percent of European
vineyards were destroyed. How did the
French wine industry bounce back? They
grafted the naturally aphid-resistant roots
of North American stock onto their stock.

Bluegill

Lepomis macrochirus

The Bluegill is a popular game fish
native to parts of eastern North America.
In New York, it is native to the Allegheny
and St. Lawrence Rivers but has been introduced statewide. In fact,
it has been introduced worldwide. As it grows, its diet becomes
increasingly dominated by small fish, and the Bluegill is now
recognized as a major threat to biodiversity in many areas.

In 1960, the mayor of Chicago gave the fish to the crown prince
of Japan as a gift. The crown prince brought it home with good
intentions. Japan was having a protein shortage. What happened?
The Bluegill has become invasive in freshwaters of Japan, reducing
the numbers of many native fish.

Eastern Gray Squirrel

Sciurus carolinensis

The Eastern Gray Squirrel is native to the eastern
United States north into Canada. It was introduced
in several areas of the western United States and
in Europe. It can be quite successful in a variety of
habitats. It is now the most common squirrel in
many urban and suburban areas in the western
United States.

It was accidentally released from
the London Zoo and was introduced to Italy as pet in the 19th century.
In England, because it has few natural predators, coupled with its high
reproductive rate, its population spread rapidly. It can now be found in
England, Ireland, and northern Italy. In Europe, it competes with and often
displaces the native Red Squirrel. It is also destructive to native trees.

Bullfrog

Lithobates catesbeiana

The Bullfrog is native to central and eastern
United States and southeastern Canada. It was
introduced in the early 1900s to the western
United States. It was accidentally introduced
during trout stocking of waters. It was also
intentionally introduced as game (for food),
released from aquaria, and used for pest
control. It was introduced in Hawaii, Mexico,
the Caribbean, South America, Europe, and
Asia.

The Bullfrog is an opportunistic predator
on aquatic, terrestrial, and flying invertebrates
and vertebrates. The Bullfrog competes with and
preys upon a variety of native species.

NOAA, Great Lakes Environmental
Research Laboratory

Opossum Shrimp

Mysis relicta

The Opossum Shrimp is native to deep glacial
lakes such as Lake Champlain, Lake George,
and the Great Lakes. It was introduced to
lakes in the western United States and
Canada as a prey species for trout and
other game fish. It is an opportunistic feeder
on zooplankton and may compete with young
trout for food. In some areas where it has been
introduced, it may substantially alter the aquatic
community—particularly native zooplankton.
This, in turn, is thought to have affected the
growth and survival of game fish.

David Cappaert, Michigan State University, Bugwood.org

TinyFarmBlog.com

Colorado Potato Beetle

Leptinotarsa decemlineata

The Colorado Potato Beetle, originally native to Mexico, moved into
the Great Plains following the spread of its host plant, Buffalo Burr.
After the introduction of the potato (which is native to
South America), the beetle switched to feeding on this
new host (potatoes). Feeding mainly on potatoes, but on
other crops as well, the beetle has expanded its range.
It is now found throughout much of North America and
has also been introduced to Europe.

The Colorado Potato
Beetle can defoliate an untreated potato crop. It is a
serious pest of potato and eggplant, and an occasional
pest of tomatoes. So, in the United States, it is a native
species feeding on an introduced species. In Europe, it is an
introduced species feeding on another introduced species.